Redwater star Oisin Stack has told how he got inspiration from young trendy priests in Catholic magazines and YouTube for his role in the EastEnders spin-off.

The Wicklow actor, 35, stars as Father Dermott opposite Jessie Wallace and Shane Richie in the new six-part show which debuted on Sunday night on RTE One.

Redwater follows much-loved EastEnders characters Kat Slater and Alfie Moon as they journey to Ireland in search of Kat’s long lost son who was adopted by an Irish family 20 years ago.

Dermott and Alfie. (Image: Patrick Redmond)

The first explosive episode unveils Fr Dermott, played by Oisin, as Kat’s son and the half-French actor said he wanted to make his character a cool priest.

He told the Irish Mirror: “Even when we were doing hair and makeup with the costume team to create the look, we looked at a lot of Catholic magazines and Youtube to see popular priests who might be doing videos or doing speeches.

“If you pick up a Catholic magazine or even when I went to a seminary in Dublin and there were young cool guys wearing hoodies and trainers.”

Oisin - who lives in Nantes, France - told of how filming in Ireland was like a “homecoming” and revealed Jessie and Shane are practically Irish.

He said: “In a way for the three of us it was the same thing, we were coming home to Ireland, Shane was born in Ireland and both Jessie’s grandmothers are from Ireland.

“For me it was a great homecoming as I was back for 5 months filming last summer.”

Another pinch yourself moment for the up and coming star was realising he would be working with Irish “powerhouse” actors for the new RTE and BBC drama series.

He said: “I was cast two weeks before they started shooting Redwater, very last minute, I didn’t know who was in it until I turned up on the first day, seeing all those powerhouse actors that I’ve grown up watching like the Guard’s Fionnula Flanagan, my heart was beating in my chest.”

Dermott Dermott (OISIN STACK) (Image: Patrick Redmond)

Oisin recalled what it was like rubbing shoulders with Robert De Niro on the set of their 2014 Luc Besson movie, The Family.

“It was probably one of the most nerve wrecking days of my life and I didn’t have a scene with him,” he revealed.

“But when our timetables collided I met him, he was early and was standing there watching me film the rest of my scene, it was the longest 20 minutes of my life.

“It was incredible, I didn’t realise it was him at first, I turned around we had just said cut and he was just sitting there, and I was just standing in front of him babbling and he laughed and just put his hand out and said nice to meet you.”